The invention concerns an opening or separating roll for an open end spinning apparatus. From the current state of technology, opening rolls for open end spinning apparatuses are common knowledge, which, for the purpose of replacement of the tooth-set, are built in multicomponent fashion. The set can be comprised of teeth or needles, which are installed on a tooth-set carrier. The said carrier is designed in the shape of a cylindrical ring, which is installed on a core piece of the opening roll and is held by a holder on said core piece.
During the operation of the open end spinning apparatus, the opening roll rotates in an opening roll housing. In this housing, bunched fibers are introduced and the individual fibers which are opened or separated out are removed through a fiber feed duct. For the function of the open end spinning apparatus, the condition of the air in the opening roll housing plays a decisive role. For this purpose, it is necessary that the opening between the opening roll and the housing is held very precisely to a specified value. The relationships within the separating roll must not be changed by means of the regularly required exchange of the toothed set, which, as is known, is subject to wear.
The patent DE-A 25 28 485 shows an opening roll in which the ring shaped tooth-set carrier is secured by force locking by a flexible element in connection with a holder for the tooth-set carrier on the core piece. The flexible element, by being subjected to a force in a radial direction, moves so that it impacts against the ring shaped tooth-set carrier from within and affixes this against the opening roll. In this way, the holder forms, at least partly, the front side of the opening roll. The width of the opening roll is thereby adjusted in such a way that the holder is made controllable as to axial direction. This is accomplished, for instance, through a threading on the core piece to which the holder itself is directly screwed, or is held by fastening means, such as screws.
The flexible element enables that the holder, even after the contact with the flexible element, still remains axially adjustable up to the desired width of the opening roll. The determination of the opening roll width is redone from start as a new operation by measurement and adjustment of the insertion depth of the holder each time there is a change in the tooth-set by the maintenance person. Subsequently, the holder, so that it will not on its own change position, must be secured by a safety element on the core piece of the opening roll. The adjustment of the width of the opening roll can, indeed, be carried out very precisely by the method taught in the patent DE-A 25 28 485, wherein the width is independent of the axial extension of the tooth-set carrier. The adjustment of the opening roll width is very time consuming and dependent for quality on the individual maintenance person.
The patent DE-A 37 30 296 discloses an opening roll in which the tooth-set carrier is designed in the shape of a ring and is secured to the opening roll by means of a holder. The axial width of the opening roll is determined by the width of the tooth-set carrier, since this lies with its front side on the core piece of the opening roll, while on the other side, the cover, that is the holder, supports itself axially on the tooth-set carrier.
From the patent DE-A 195 20 345 is known an opening roll in which the holder and the tooth-set carrier are made integrally as one piece, wherein the tooth-set carrier supports itself axially on the core piece of the opening roll, and thereby the width of the opening roll is determined.
The known opening rolls, in which the tooth-set is changeable, have the disadvantage that either the installation of the opening roll is time and money consuming and the width of the opening roll must be reset anew every time, or that the tooth-set carriers, since they determine the width of the opening rolls, must be produced with great precision and thus expensively. Never-the-less, the problem arises in these embodiments that the width of the opening roll, in spite of more exact manufacture, is still not precisely determined, since the tooth-set, following manufacture, in many instances must be coated, the result being that by material accumulation the width of said tooth-set when so coated varies from that before coating. Thus, the width of the opening roll varies, even with the most exact manufacturing procedures.